Removable denture attachment



Feb. 5, 1963 H. w. GOODMAN 3,076,264

REMOVABLE DENTURE ATTACHMENT Filed Dec. 8, 1959 FIG I 3 Sheets-Sheet 1 BRIDGE TOOTH BT f PIER TOOTH PT FIG2 INVENTOR Hrman Wfoodmmz Jaw-w 61k ATTORNEY Feb. 5, 1963 H. w. GOODMAN REMOVABLE DENTURE ATTACHMENT 3 Sheets-Sheet 2 Filed Dec. 8, 1959 FIG 3 REST SEAT lo FIG 4 FIG 5 LATCHING BOSS l6 RECESS l4 HOUSING l8 BLOCK 2O INVENTOR Herman Wgooalman ATTORNEY APERTURE l9 Feb. 5', 1963 H. w. GOODMAN REMOVABLE DENTURE ATTACl-IMENT Filed Dec 8, 1959 3 Sheets-Sheet 3 Q INVENTOR Wfioodman ATTORNEY Herman United States This invention relates to dental .bridgework, more especially to a new attachment means for removable partial dentures; and it is entitled Removable Denture Attachment.

This attachment comprises an outer spring latching detent adapted to urge resiliently (yieldably) against one outer side of the tapered surface of a pier (natural) tooth, together with a rigid (unyielding) reach around arm which extends halfway around the pier tooth and which is i adapted to rest and brace statically at its other side, i.e., the side of said pier tooth which is opposite the latching detent.

The invention is believed to inhere (1) in the latching detent per se and (2) in its combination with said reach around bracing arm, the latter being so arranged as to provide a new mode of coaction, which distinguishes it from conventional types of dental bracing arms adapted to cooperate with pier (abutment) teeth. i r

The two elements of this new denture attachment (its combined spring detent and reach around bracing arm) cooperate in a novel manner with each other and also with the pier tooth. This mutual coaction is achieved-by joint spring press and stationary rest actions (dynamic and static), to stabilize the pier tooth (brace it) while retaining the removable bridge on the pier tooth and on the gum ridge in ones mouth.

By latching detent is meant, generally, a spring actuated retentive device (attachment) for holding a partial denture removably in place; and by outer is meant, specifically, that type of detent which engages theoutside surface of a pier tooth; An example of an outer latching detent, early inthe art, is shown in Bennett 832,528, as distinguished from the conventional inner latching detent exampled by Sorensen 1,705,504 having a male part which removably latches (detent fashion) into a socket wholly inside the perimeter of a pier (sound) tooth.

By reach around arm (noted in the second and third paragraphs hereof) is meant that form of removable denture having a rigid arm which reaches halfway around a pier (abutment) tooth and which rests (statically) at and against the far (opposite) side of said pier tooth, to

- site each other.

Such a rigid reach around arm for removable dentures is also known as a reciprocal arm. An example of such dental bridgework is given in a publication entitled History Partial Dentures, Journal American Dental Association, September 1941, pages 1399 through 1408, Girardot, D.D.S., particularly on page 1405 thereof iliustrating the retentive means as a spring latch-on clasp.

Another example oflater date is shown in US. Weissman Patent 2,748,480, filed March 29, 1955, and issued June 5, 1956, wherein the retentive means is disclosed as a spring-actuated plunger, instead of a spring clasp.

A study of that branch of denture technique herein involved reveals that the stabilizing function of a reach around bracing arm is wholly in contrast to and serves'a purpose entirely different from that of a dental clasp, as exampled in Williams 1,412,224 and other like prior art denture retaining clasps. The arm and the clasp are not to be confused, despite the lack of clarity in prior illustrations and descriptions concerning them.

The term pier tooth means a sound or natural tooth to which the denture attachment is applied, but in the prior art it is often referred to as an abutment and sometimes an anchor tooth, etc. Note also that the term reach around arm is sometimes referred to in the prior art as a reciprocal member or arm.

A typical form of removable denture comprises a saddle adapted to rest on the gum ridge or margin, with one or more bridge (false) teeth carried by the saddle, together with an attachment for retaining the bridgework in place by fastening it to one or more pier teeth in the mouth. It is from this old practice that the present invention stems and proposes the improvements herein.

It is a main purpose of this invention to resolve problems discovered in the removable denture art (1) specific to the known type of outer latching detent, (2) also its reach around bracing arm, and (3) the combination of the two. The new structural arrangements herein are believed to improve the conventional form and the utility of all three aspects noted.

It is a particular purpose to provide (1) a new structural form of spring actuated latching detent having a leaf-spring, as distinguished from the old coil spring and plunger type, and (2) a new form of reach around bracing arm, providing an improved combination when the two are used together in a removable denture restoration.

In the new combination herein, the pier (sound) tooth is well protected against the force of the spring actuated latching detent. This is by reason of a new form of reach around rigid arm and its bracing rest in extending about halfway around a pier tooth, for supporting the latter on the far side, remote from the removable denture.

Such new arrangement provides an improved mode of operation when removing the denture from ones mouth and when replacing it therein. The reason therefor is that said reach around arm of rigid form is static (never places a force against the pier tooth) and stabilizes the pier tooth (braces it) against the spring pressure of this improved latching detent when the latter is moving into,

place, also while it is in working position, and likewise when it is being removed from the mouth.

The drawings:

The accompanying drawings now considered, along with this specification and claimed subject matter, disclose the best mode contemplated in applying the prinple of the invention and understanding the problems discovered as well as the new results achieved. Since these teachings may suggest structural changes to others, it is apparent that later modifications may well be equivalents and thus the same in spirit as this invention, as understood by a comparison thereof with the prior art.

Denture parts are quite small. Therefore, in planning the illustrations herein, the smaller components were first visualized and then illustrated oversize, in order to appear prominently and be understandable when reduced to that small size necessary for conventional printed patent format. In view of such enlargement for clarity of the important parts of minute size, it follows that the less important parts (such as the bridge saddle, its restoration tooth or teeth, and the pier tooth, all exemplary) may seem somewhat large in the drawings. Even so, they are thus illustrated in order to maintain approximate proportions.

In the drawings, the pier tooth is at the left-hand side, and the removable denture (saddle and bridge tooth) is at the right. For simplicity, the illustrations are shown as a lower bridge. Also, note that only one end of the bridge need be shown to illustrate the invention.

It is helpful in this study of the drawings to observe 7 that all the views are made from the insideof the mouth,

3 looking outward. This is an appropriate viewing position, since the reach around arm (lingual) is on the inside of the mouth. It is not seen from the front.

The several views (figures) in the drawings are arranged in sequence of operation and summarized by full description of each in order to disclose the invention at the outset, thus making for brevity of detail when later referring to the reference characters (parts numbering and lettering) noted in the drawings.

In the illustrations, FIG. 1 has the names of conventional parts printed thereon, and letters are used as ref erence characters pointing to these old parts. In contrast thereto, the new parts are pointed out bynumbers, and

said numbered new parts have their names printed on subsequent views, beginning with FIG. 3.

Accordingly, the printed legends (names of parts, with letters and numbers) are set up on FIG. 1 for old elements (lettered) in this new combination, also the legends (names) for new parts (numbered) beginning with FIG. 3, are consistently used in this disclosure-thus making for uniformity in terminology, helpful in interpreting the invention, by avoiding the use of several different names for one and same part so prevalent in prior descriptions noted during this research.

The illustrations to follow are in part schematic, in the interest ofclarity, to demonstrate the principle of the invention, rather than follow exactmanufacturing technique where the latter is not critical in respect to the points of improvement.

FIG. 1 is a perspective, showing this new removable denture (its combined latching "detent and bracing arm) poised in spaced relation above a gum ridge and pier tooth, in readiness'to be pushed down and latched thereonto.

FIG. 2 shows the nextstep, i.e., the removable bridge has been set in final position (pushed down) onto the gum ridge, then latched by its spring detent resiliently engaging the rear side of the pier tooth at a high point on the latter. This view also shows the reach around arm bracing the far side of the pier tooth, thus stabilizing it against the tension (push) being urged by thespring latching detent.

FIG. 3 is a top view of FIG. introduces the next view.

Now it is explained that, in FIGS. 1 and 3, the latching detent unit is abbreviated for clarity, by merely showing, schematically, its leaf spring means in dotted lines. In other views, this leaf spring is shown in solid lines, enlarged in detail, and within a tubular housing protecting it during handling and also enclosing it against food accumulation.

FIG. 4 is a'section approximately on the line 4, showing the reach around arm broken away, with the retentive detent unit in elevation.

FIG. 5 hasto do with the manufacture of the denture and shows the two separate units thereof ready for final assembly. The spring latching detent unit is at the left and in assembly alignment with a recess formed in the bridge unit at the right, thus ready to be pushed into a 2, and the section line 4 recess formed in the bridge unit, where it is held in place by any suitable means, such as a close and frictional fit. It can be removed from the bridge unit by a dentist if need be for inspection or repair and replacement.

The next three views demonstrate a novel relation of the two units, by which the rigid reach around bracing arm sets its bracing rest' statically against a rest seat on the pier tooth and braces (stabilizes) it in repose before the spring detent applies its latching pressure thereto.

FIG. 6 is an action view, showing the removable denture being set in position, emphasizing that the reach around arm with its bracing rest has first statically engaged the pier tooth on its far side before the spring detent starts pushing against it, as in the next view.

In the two views to follow, the bracing'arm is omitted,

but its bracing rest (in section) is in place on the far side of the pier tooth.

FIG. 7 is another action view, showing that the removable denture is sliding into place, further down on the pier tooth than in FIG. 6, also that the latching detent has started engaging the round top corner outer surface of the pier tooth, and it is about ready to latchingly slide down the inward taper formation of the latter.

FIG. 8 is an at-rest view of the complete dental restoration. The removable denture is in final latched position, the same as in FIGS. 2, 3 and 4. The leaf spring detent is tensioned (spring loaded) and is exerting (dynamically) its yieldable latching force against the pier tooth. However, the reach around arm and its bracing rest are holding (statically) the pier tooth in a state of repose and thus counteracting (absorbing) the force of the spring loaded detent. This mode of removable denture operation preserves the root structure and normal health condition of the pier tooth.

It is thought that the foregoing description and the illustrations constitute an overall teaching of the invention. Nevertheless, the drawings are now referred to again for the purpose of briefly pointing out particulars. First, it is noted that a portion of a gum ridge GR in ones mouth is shown schematically. The gum ridge GR carries a pier tooth PT, a natural or sound tooth, one of which is sufficient to explain this invention.

Next, it is observed that a suitable form of conventional bridge saddle BS carries one or more bridge teeth BT. Manufacturing practice differs, but one form, among others, of producing a removable denture is to make the bridge saddle BS of dental metal, the bridge tooth or teeth BT of plastic, and then mount the bridge tooth in the saddle in any suitable way (cemented or molded) thereon.

The pier tooth PT is prepared by the dentist with a fiat vertical rest surface, in the form of a rest seat 10, on its far side, the plane of which is perpendicular to the longitudinal axis of the gum ridge GR and of the bridge saddle BS. The rest seat 10 is formed on or near the (axis) center line of the bridge saddle BS and on the side opposite to the removable denture latching detent. 'The near or detent side of the pier tooth PT either has a natural inward taper from its occlusal bulb (upper portion of natural tooth) toward the gum ridge GR, else it is so prepared by the 'dentist with the taper (slant), as shown in the views.

Coming now to the denture per 'se, it is noted that a hand stabilizing support, in the form of a bracing rest 11, is integrally formed on the outer free end of a rigid reach around bracing arm 12. The bracing rest 11 of the arm is adapted to set in its final rest (static) position against the flat rest seat 10 of the pier tooth PT when the removable denture is in its operative position (FIGS. 2, 3, etc.). The other (inner) end of the bracing arm 12 is carried on or integrally formed with the bridge saddle BS. The bracing arm 12 is contoured and reaches about halfway around the pier tooth PT. The upper tip end of the vertical bracing rest 11 has a horizontal occlusal rest of known form (FIG. 1), which seats on the pier tooth PT (FIG. 2) and serves as a down stop for the bridge, thus limiting its pressure on the gum ridge GR.

Inasmuch as the rigid bracing arm 12 does not perform the function of an ordinary clasp, the enlarged illustrations particularly reveal (FIGS. 2, 3, 4 and 6) a clearance space 12C between said arm and the pier tooth PT. Actually, in a commercial or mouth size denture, the parts are so small that the clearance 12C would not be apparent and, consequently, be confused or mistaken for a spring tensioned clasp, as so frequently occurs in prior literature due to inadequate illustration and vague description.

An example of one form of the spring latching detent unit and its slip-in mounting in the bridge saddle BS are next described. Observe that FIGS. 1, 4 and 5, etc.,

illustrate an arcuate recess 14 formed in the bridge tooth BT, i.e., in the bridge unit. The recess 14 conforms to the overall shape of the detent unit (noted at the left side in FIG.

The upper curved wall of the recess may be defined by the bridge tooth BT, and the lower straight wall thereof may be defined by the bridge saddle BS. The recess 14 is in part L-shaped, with its front upright portion formed open for receiving the detent unit, and its longer horizontal portion closed by the saddle BS.

The spring latching detent unit includes an arcuate leaf spring 15, a lower portion of which is disposed horizontally and an upper or outer flexing portion of which is in upright position. The leaf spring 15 is sometimes referred to as an L-spring, and it conforms to the general shape of the L-shaped recess 14 in the bridge unit. A detent pressure latching boss 16 is carried on the upper outer free end of the leaf spring 15 and is directed toward the pier tooth PT.

A tubular housing 18 is also of arcuate shape, similar to that of the L-shaped leaf spring 15. The housing 18 includes an inner lower horizontal portion and an outer upper portion. This tubular housing is rectangular in cross section, and its upper end is provided with an aperture 19 through which the detent boss 16 operatively (movably) protrudes.

The housing 18 completely encloses and protects the leaf spring 15, the inner lower end of which is fastened (anchored) against flexure in the housing 18, by any suitable fastening means, at its far and lower end, by a block 20. The spring 15 is flexibly free within its housing 18 from the latching boss 16 back to its fastening block 20 or other fastening means.

The tubular detent unit 18 as a whole is inserted in the bridge unit recess 14, with a sliding fit between the rear end (the block end 20) of the detent housing 18 and the similarly shaped rear portion of the recess 14. The close fit, thereby established, acts to hold the detent unit 18 firmly in place in the position shown in FIG. 4 and other views. The upper curved back wall portion of the bridge unit recess 14, in the bridge tooth BT, acts as a stop for the tubular housing 18, i.e., the detent unit; and it snugly nests (but removably) in its caging recess 14.

. In use (as in FIG. 8 and others), the pressure exerted by the spring latching boss 16 continuously urges the detent inwardly of its recess 14. Accordingly, the above described close or snug fit, of the detent housing 18 in its bridge recess 14, need be merely a freely sliding contact fit, thus permitting a dentist to withdraw the detent unit 18 as a whole, for inspection, repair and replacement, if need be.

From the foregoing study, it is noted that the bracing rest 11 on the bracing arm and also the rest seat on the pier tooth are of large area, thus providing a spreadsurface static contact (reposed engagement) between them. This feature avoids point contact between the two parts, distributes the effective bracing effort, and reduces wear.

Also, it is seen that the vertical length of both the pier tooth seat 10 and the bracing rest 11 of the arm is longer than the effective latching travel of the detent boss 16, from the latters first point of contact with the pier tooth PT (FIG. 7) to its final position (FIG. 8). This feature is achieved by locating the upper tip end of the bracing rest 11 above the horizontal level of the detent latching boss 16 and the lower tip end thereof below said level of the boss, as more fully described in the following:

FIG. 8 highlights the feature noted in the preceding paragraph. Note that the latching boss 16 has made pier tooth contact in FIG. 7, but that the leaf spring has not started to flex. That same position of the boss 16 is shown in dotted lines in FIG. 8, wherein one dimension comparison indicator 16A marks off the distance (length) of the effective overall latching travel of the boss 16, and another indicator 11A marks the vertical length (height) of the rest seat 10 and of the bracing rest 11.

At a glance, it is seen that the effective length 11A of the bracing rest 11, being greater than the effective travel 16A, provides for and implements the new mode of operation demonstrated on sheet 3 of the drawings (as heretofore noted). In other words, when inserting the bridge, its bracing arm 12 supports bracing rest 11 in a position to advance it into reposed bracing engagement with the pier tooth rest seat 10 first and before the pressure of the latching boss 16 is applied thereto. Likewise, when removing the bridge, the bracing rest 11 maintains its stabilizing engagement with the pier tooth rest seat 10 until and after the spring loaded latching boss has moved away from the pier tooth.

Another feature of importance, arising out of the new structural arrangement of the detent unit 18, relates to the elevated or high position of its latching boss 16. Observe that it is high above the gum ridge GR and more particularly the bridge saddle BS. This height of the latching boss 16 is achieved by reason of the arcuate detent unit 18 having the unique up-curve arrangement which locates the upper end of the leaf spring 15 and its boss 16 near the upper portion of the pier tooth PT and just under the bulb of the latter.

Accordingly, thehigh position of the latching boss 16, as noted in the preceding paragraph, leaves a generous open space between the removable denture per se and its pier tooth, and thus the denture is less likely to collect food in and around the latching detent.

The several improvements featured herein are believed to meet a need in the dental art and to provide a better form of removable denture attachment, in respect to the two components, i.e., the stabilizing arm means and the latching detent, as well as the combination thereof for partial dentures.

What is claimed is:

l. A denture attachment comprising an elongated flat leaf spring, which is generally L-shaped, enclosed within a tubular housing of like shape, and about the same length as the spring; the housing being rectangular in cross section, with its enclosing walls sufficiently spaced apart to permit free fiexure of the leaf spring; said enclosed leaf spring being fixed at one end to a wall of the housing, and flexibly free at its other end within the housing; and a latching boss on the flexibly free end of the leaf spring, extending through an orifice formed in the housing, and adapted to flex the leaf spring and actively tension it for resilient engagement of said latching boss against the outer surface of a pier tooth.

2. A removable denture comprising a bridge, a latching detent unit, carried on said bridge, and having spring means with a latching boss adapted to resiliently engage the outer surface of a pier tooth on its near side; in combination with a rigid reach around bracing arm, one end of which is carried by said bridge, the other end being free and adapted to extend partway around the pier tooth, and statically engage its far side, in order to stabilize it against the pressure of the spring means of the latching detent unit, said free end of the bracing arm being characterized by a bracing rest having a vertical length greater than the effective latching travel of said boss, whereby the bracing rest engages the pier tooth before the latching boss does so and disengages it after the boss does so, when inserting and removing the bridge, respectively.

3. In an attachment for removable dentures, having a latching boss adapted to resiliently engage the outer surface of a pier tooth; that improvement in said attachment which comprises an arcuate leaf spring, with one end thereof disposed in a horizontal position; and the other end of the leaf spring being disposed in an upright position, with said latching boss carried on the upright end, an arcuate tubular housing enclosing the arcuate leaf spring, and means fastening the end of the horizontal portion of the leaf spring in the housing, the horizontal portion of the housing being adapted to be mounted in the lower portion of the removable denture,

and the tubular housing being provided with an aperture, through which said latching boss operatively protrudes, thus adapting said boss to spring latch against the upper portion of said pier tooth, and leaving an open space under the boss and between said denture and pier tooth.

4. In an attachment for removable dentures, having a latching boss adapted to resiliently engage the outer surface of a pier tooth; that improvement in said attachment which comprises an arcuate leaf spring, with one end thereof disposed in a horizontal position; and the other end of the leaf spring being disposed in an upright position, with said latching boss carried on the upright end, and an arcuatetubular housing enclosing the arcuate leaf spring and being provided with an aperture, 15 through which said latching boss operatively protrudes, thus adapting said boss to spring latch against the upper portion of said pier tooth, and leaving an open space under the boss and between said denture and pier tooth, said removable denture being provided with a recess, conforming to the shape of the tubular housing, and thus adapting said tubular housing to be mounted in the removable denture.

References Cited in the file of this patent UNITED STATES PATENTS 832,528 Bennett Oct. 2, 1906 992,996 Stefhan May 23, 1911 10 2,631,373 Timm Mar. 17, 1953 2,748,480 Weissman June 5, 1956 2,826,814 Sappey et 'al. Mar. 18, 1958 OTHER REFERENCES Girardot, Raymond 1.: History and Development of Partial Denture Design, pages 1399-4408, Sept. 1941 (copy in Scientific Library).

Dee & Co. Leaflet (received in Patent Office Oct. 9, 

1. A DENTURE ATTACHMENT COMPRISING AN ELONGATED FLAT LEAF SPRING, WHICH IS GENERALLY L-SHAPED, ENCLOSED WITHIN A TUBULAR HOUSING OF LIKE SHAPE, AND ABOUT THE SAME LENGTH AS THE SPRING; THE HOUSING BEING RECTANGULAR IN CROSS SECTION, WITH ITS ENCLOSING WALLS SUFFICIENTLY SPACED APART TO PERMIT FREE FLEXURE OF THE LEAF SPRING; SAID ENCLOSED LEAF SPRING BEING FIXED AT ONE END TO A WALL OF THE HOUSING, AND FLEXIBLY FREE AT ITS OTHER END WITHIN THE HOUSING; AND A LATCHING BOSS ON THE FLEXIBILY FREE END OF THE LEAF SPRING, EXTENDING THROUGH AN ORIFICE FORMED IN THE HOUSING, AND ADAPTED TO FLEX THE LEAF SPRING AND ACTIVELY TENSION IT FOR RESILIENT ENGAGEMENT OF SAID LATCHING BOSS AGAINST THE OUTER SURFACE OF A PIER TOOTH. 